The present invention relates generally to snow plows, and more particularly to snow plows that are used in conjunction with small, lightweight vehicles. For example, the snow plows of the present invention are especially adapted to be used, i.e., to be pushed, by lighter weight vehicles such as so called UTVs (utility vehicles), ATCs (all terrain cycles), ATVs (all terrain vehicles), and the like, usually powered with a 4 to 50 horsepower engines. Such snow plows have the ability to readily access snowy destinations and there to be run efficiently and at low cost. Many areas, particularly those wherein there is a moderate to large amount of snow, are particularly suited to being cleared by the plows of the present invention.
One of the difficulties that has been encountered with smaller, light weight plows of the type with which the invention is concerned, has been their inability to deal with unseen hazards such as tree stumps, sunken rocks or curbs, and parking place dividers made from concrete, and which are disposed toward the lateral edges of the plow. Such obstacles may be easily covered by snow, and when the snow plows encounter them, they are not seen by the operator until the blade contacts the obstacle at the edge or toward the edge of the plow. If such an obstacle is hit by the plow toward the center of the blade, the blade will tilt forward, and then skip over the obstacle. This does not create the risk of damage to the plow. However, off-center contact with existing units holds out the risk of damage, even serious damage, to the plow.
Most of the problems with snow plows such as those with which the present invention is concerned, is that whatever obstacles, such as parking place markers or tree stumps, are encountered at the outside edge of the plow create the risk of damage to the plow assembly. Because by far the majority of snow plowing is done with the blade at an angle to the direction of movement, the need for the invention is paramount.
Consequently, of most concern are obstacles of the above-mentioned kind lying toward the edge of the area being plowed.
It is therefore an object of the present invention to provide a safety device for a snow plow blades which would enable the blade of the plow, if struck well off center, to deflect or rotate rapidly without material damage, such blade being rotated about its vertical axis, that is, about the center of the structure supporting blade.
Another object is to provide a safety measure or protective device, particularly for the edge of a snow plow device.
It is a further object to provide such a safety device which will enable the plow blade to be deflected about from its stationary or pre-set position, to an offset or further position, and thereafter be able to reset to its original position without damage, so as to resume plowing.
A more particular object is to provide a snow plow mounting device which includes a novel clutch mechanism for holding the blade at a selected angle used in plowing, but which blade will rotate or deflect to a greater or less extent upon encountering a fixed object.
A further object is to provide an axially responsive safety clutch mechanism which may transiently disengage a fixed part from a rotary part if it encounters a hidden obstacle.
A still further object is to provide a safety clutch for mounting on a snow plow, the clutch preferably having a pair of domed plate members with one such plate having a large plurality of protruding portions or elements and the other plate having corresponding plural pockets, with the protuberances and the pockets being in nested relation, and the two plates being rotatable with respect to each other when the axial force holding them together is overcome.
A further object is to provide a clutch having a large number of stable positions, so that the plow may be deflected to varying extents, depending on the nature of the obstacle, the speed and angle of the plow, etc.
Another object is to provide such a clutch which may be adjusted for a desired break-away force.
Another object is to provide a clutch with an axial handle and a series of Belleville washers or springs which can readily adjusted for a predetermined break-away force merely by manipulating the handle.